Green Arrow Vol 2 18

"The Horseman, Part 2": Somewhere in a Seattle penthouse, Mr. D'Agostino - a mob boss - threatens that after killing a stripper by crucifying her, his henchman Fredo has one day to kill the man who is looking for her.

Synopsis for "The Horseman, Part 2"

Somewhere in a Seattle penthouse, Mr. D'Agostino - a mob boss - threatens that after killing a stripper by crucifying her, his henchman Fredo has one day to kill the man who is looking for her.
Meanwhile, Lt. James Cameron attends the autopsy of the stripper known as Dawn. The coroner reveals that she was still alive when she had been crucified, but had died of suffocation as a result. She notes that the there would have to have been two culprits - ruling out the mysterious Horseman that the Lieutenant suspected.
Later, outside a strip club called Pink Freud's, the Horseman attacks the proprietor in search of Dawn, and unaware that she has been murdered. When he leaves, he is accosted by several bikers belonging to the mob, and they come to a standoff. Suddenly, Green Arrow appears, and he and the Horseman take out the entire gang.
Oliver still believes that the Horseman is guilty of Dawn's murder until he accuses him. The man's obvious distress makes Oliver realize that a man would not keep hunting for the woman he killed. Oliver explains what happened, and asks what reason someone would kill her.
The Horseman explains that she had become addicted to drugs, and was forced into sex work. She had tried to quit, but was forced to stay. So, she contacted a cop (the Horseman himself), who was more concerned with his career than her well-being. He had helped her get into a meeting of several Canadian mob-bosses, and collect evidence. Unfortunately, before she could turn over the evidence, she was sold to a Seattle mob boss. the Horseman suspects that when she tried to use the evidence to blackmail her way out of the industry, she was killed.
Together, Oliver and the Horseman head to the club that Dawn used to work at, just in time to see Lt. Cameron and his men arresting the murderers. Oliver investigates her dressing room and finds the key to a safety deposit box. He accompanies the Horseman to the Canada-US border, giving him the key, and suggesting that it will open the location of the evidence she had collected.
As Oliver predicted, the Horseman, who is actually an RCMP officer, finds the evidence in a Vancouver bus terminal, and promises not to let Dawn down.